How do plants communicate with each other? Most people have no idea that plants can communicate with other plants, and this can make for a fun active learning exercise during a botany lesson. Get students to brainstorm possible means of communications, either as a class or in small groups, and discuss how such signals would be detected. Changes in color? Plants don’t have any known means of detecting this. Smell? Well, plants don’t have noses, but many receptors exist inside cells and on the surface of cells. A volatile chemical can move through the air from one plant, be absorbed by another plant and cause changes in gene expression. You can make this as simple or complex as you like, including chemical names, genes expressed, or for primary school students, you can easily talk about one plant sending a message that it has been damaged by a grazer and another plant receiving the message and tasting bad to grazing animals.
That one has been known about for a while, but one that has just been discovered is communication by sound. Apparently, the roots of corn saplings (corn that has germinated and has begun to grow) both produce and detect a clicking noise…
And her intuition was right. She, along with fellow researchers Stefano Mancuso and Daniel Robert, used powerful acoustic instrumentation which allowed them to hear clicking sounds coming from the roots of corn saplings. They also found that when they suspended the young roots in water and played a continuous noise at 200 Hz – a similar frequency to the clicks – the plants grew towards the source of the sound.
Seriously? A sound influences root growth? Science is so cool! They have no idea how this works, but that is pretty cool in itself. This could make for a very interesting discussion as well, with students developing hypotheses as to how the plants are both making and detecting the sound. A great lesson to be had here is that there are always new things to discover, and not knowing the answer to a question means that there are still things to learn.
Another fun discussion topic for any class can be about how strange beliefs spread through society. For instance, the claims that the world will end this year (2012), based on Mayan prophecy is a fun one. In fact, you can make this as simple or as complex as you like, asking students to look for articles that are both critical of or in support of these claims and discuss what makes for a good argument and what doesn’t. For a simple one, you can just talk about how the people that study Mayan history are completely annoyed by the 2012 hysteria. One easy visual is to show students a 2012 and a 2013 calender, pointing out that the world doesn’t end when you get to the end of one calender year.
Of course, this tidbit and the previous one fit together neatly. How do you tell good information from bad? Apply your baloney detection toolkit, which is made easier with the careful use of the internet.
Ever want to talk about exoplanets (planets orbiting other stars)? This is a good place to start… You can see all the planets that we have discovered so far (as of June 2012), with the knowledge that we are discovering more all the time. This can lead into a discussion of how we discover planets. Phil Plait gives a great video explanation, which makes for a good bit of media to add to the classroom.
And how could I not mention that the REAL Skywalker ranch is getting some historic preservation attention. The set used in Episode IV of the Star Wars saga as the home of a Owen, Beru and a young Luke Skywalker is getting some well deserved maintenance and care. A trip to Tatooine… I mean Tunisia never sounded so good.